| Inside Vax/Vms |
| Using Command Procedures |
| By |
| Master Blaster |
Advanced Telecommunications Inc.
Note: The following is geared for the more advanvced hacker.
Part 1: Using Command Procedures.
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You can use command procedures to automate sequences of
commands that you use quite often. For example, if you always
use the DIRECTORY command after you move to a Sub-Directory
where work files are kept, you can write a simple command
procedure to issue the SET DEFAULT and DIRECTORY commands for you.
the following example, GO_DIR.COM, contains two commands:
$ Set Default [perry.accounts]
Instead of using each command alone, you can execute GO_DIR.COM
with the @ command:
this command tells the DCL command interpreter to read the file
GO_DIR.COM and executes the commands in the file. So the command
interpreter sets your default directory to[PERRY.ACCOUNTS] and
issues the DIRECTORY command.
note: DCL means Digital Command Language. (sorry)
Formatting Command Procedures
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Use the DCL command CREATE to create and format a command
procedure. When you name the command procedure, use the default
file type COM. If you use this default, you don't have to use the
file type when you execute the procedure with the @ command.
Command procedures contain DCL commands that you want the DCL
command intepreter to execute and data lines that are used by
these commands. Commands must begin with a dollar sign. You can
start the command string just after the dollar sign.
Data lines do not start with a dollar sign. Data lines are used
as input data for commands. Data lines are used by the most
recently issued command.
the following example shows command and data lines in a command
did you get my memo?
Show users thomas
The first line is a command and must start with a "$". The next
lines are data lines that are used by the mail function; these
lines must not start with "$".
Using Multiple Lines for One Command
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If you are writing a command that includes many qua|ifers,
ou can make the command procedure more readable by |isting the
qualifers on seperate lines rather than running them together. To
do this, use the hyphen as a continuation character. Don't start
the continued line with "$". For example:
$ print test.out -
Executing Command Procedures
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You can execute command procedures in two modes: interactive
and batch. In interactive mode, the commands in the command
procedure are executing as if you were typing them. You cannot
execute any other commands from your computer. In batch mode,
the system creates a seprate process to run the command
procedure. After you use a batch job you can continue to use
the system while it executes.
Executing Command Procedures Interactively
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To execute a command procedure interactively, type the "@"
command followed by the file specifications. If you don't enter
the entire command specification, the system will use the current
disk, directory, and file default.
Changing Command Levels
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A command level is the DCL level from which you issue
commands. When you log in and type commands at your Computer,
you are issuing commands at your level zero. If you execute a
procedure, the commands in the procedure are executed at command
level 1. When the procedure ends and the DCL prompt is on your
screen, you are back at levil zero.
A System Login File
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If a system login fi|e exists, it is executed before the
personal file. When the system login file ends, control is
passed to the personal login file. System and group login files
allow a system manager to make sure certian files are executed
when a person logs in.
To make a system login file, you have to have a managers account,
you use the name SYS$SYLOGIN to make the login file.
Personal Login Files
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After executing a system or group login file, the system
executes a personal login file. Use a personal login file to
execute gommands that you want to that you want to issue
everytime you login. Name the login command procedure LOGIN.COM
and put it in the default login directory.
Defining Parameters or Qualifers
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You can create a command procedure that specifies only
parameters and(or) qualifers and then use the command procedure
then a DCL command string. This type of command procedure is
useful when there is a set of parameters or qualifiers that you
requently use with one or more particular commands. To execute
the command string where you would normally use the qualifiers or
For example: You could greate a command procedure that contains
To use this command procedure, execute it on the command line
where you would otherwise place qualifiers. For example, if you
name the command procedure DEFLINK.COM, you would use the
following command line to link to an object module name
SYNAPSE.OBJ with the qualifiers that you specified in the command
$ LINK SYNAPSE@DEFLINK
The next example shows a command procedure named PARM.COM that
To execute the procedure, use it in a command string in place of a
$ DIRECTORY @PARAM
As the others in this set are completed, they should stay in a
H)ackRite 1986 - Advanced Telecommunications Inc.